NEET Chemistry NEET PYQ-Carboxylic Acids

  • question_answer
    A mixture of 2.3 g formic acid and 4.5 g oxalic acid is treated with conc. \[{{\text{H}}_{\text{2}}}\text{S}{{\text{o}}_{\text{4}}}\]. The evolved gaseous mixture is passed through KOH pellets. Weight (in g) of the remaining product at STP will be [NEET - 2018]

    A) 2.8

    B) 3.0

    C) 1.4

    D) 4.4

    Correct Answer: A

    Solution :

    [a] \[\underset{2.3g\text{ or }\left( \frac{1}{20}\text{mol} \right)}{\mathop{\text{HCOOH}}}\,\xrightarrow{\text{Conc}\text{.}{{\text{H}}_{\text{2}}}\text{S}{{\text{O}}_{\text{4}}}}\underset{\frac{1}{20}\text{mol}}{\mathop{\text{CO(g)}}}\,\text{+}{{\text{H}}_{\text{2}}}\text{O(l)}\]
    \[\begin{align}   & \text{COOH}\xrightarrow{\text{Conc}\text{.}{{\text{H}}_{\text{2}}}\text{S}{{\text{O}}_{\text{4}}}}\underset{\frac{1}{20}\text{mol}}{\mathop{\text{CO(g)}}}\,\text{+}\underset{\frac{1}{20}\text{mol}}{\mathop{\text{C}{{\text{O}}_{\text{2}}}}}\,\text{(g)+}{{\text{H}}_{\text{2}}}\text{O(l)} \\  & \underset{4.5g\,\,or\,\,\left( \frac{1}{20}\text{mol} \right)}{\mathop{\begin{align}   & \text{ }\!\!|\!\!\text{ } \\  & \text{COOH} \\ \end{align}}}\, \\ \end{align}\]Gaseous mixture formed is \[\text{CO}\] and \[\text{C}{{\text{O}}_{\text{2}}}\]when it is passed through KOH, only \[\text{C}{{\text{O}}_{\text{2}}}\]is absorbed. So the remaining gas is CO.
    So, weight of remaining gaseous product CO is
    \[\frac{2}{20}\times 28=2.8g\]
    So, the correct option is


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